Prevention, diagnosis, treatment

We are conducting a series of clinical trials on corneal infection to improve treatment outcomes and prevent severe disease:

Chlorhexidine vs natamycin

Fungal keratitis accounts for more than half of microbial keratitis in tropical regions. The preferred treatment is topical natamycin, an antifungal drug. Some reports suggest approximately one quarter of patients receiving natamycin continue to progress to serious consequences and ultimately blindness or the loss of the eye. It is also relatively expensive, difficult to formulate and unavailable in most countries in sub-Saharan Africa.

Our research focused on chlorhexidine, an existing, cheap and easily formulated general antiseptic. It has been used in various forms in ophthalmology for >30 years, including as an eye drop preservative and for sterilizing contact lenses.

We performed a randomized controlled, single-masked, noninferiority clinical trial, testing topical chlorhexidine 0.2% vs. topical natamycin 5%. Patients were randomly allocated to receive either treatment for their fungal keratitis.

354 patients were enrolled between 2019 and 2020, and their vision (best spectacle-corrected visual acuity at 3 months) and longer-term eye health (perforation or therapeutic penetrating keratoplasty by 90 days) assessed after treatment.

Overall, natamycin treatment was found to have better outcomes then chlorhexidine. However, chlorhexidine appears to be effective for less severe cases. Therefore, in situations where natamycin is not available, chlorhexidine could potentially be used as a second line alternative.

This study was important in the field, providing evidence that the current standard of care has benefits compared to a cheaper and more readily available alternative. Future research can focus on other treatments that could further improve eye health in these patients

Publication

Hoffman JJ, Yadav R, Sanyam SD, Chaudhary P, Roshan A, Singh SK, Singh SK, Mishra SK, Arunga S, Hu VH, Macleod D, Leck A, Burton MJ. Topical Chlorhexidine 0.2% versus Topical Natamycin 5% for the Treatment of Fungal Keratitis in Nepal: A Randomized Controlled Noninferiority Trial. Ophthalmology. May 2022. https://doi.org/10.1016/j.ophtha.2021.12.004

Acknowledgements

We would like to thank the Wellcome Trust for funding this work and Sagarmatha Choudhary Eye Hospital, the Eastern Region Eye Care Programme, Nepal Netra Jyoti Sangh and the Nepal Health Research Council for their partnership.